How do I know what Muncie 4 speed I have?
Another way to confirm that the transmission is original to your car is most Muncie four-speed transmissions will have a Vehicle Identification Number (VIN) number stamped on the main case. The engine and transmission were stamped at the same time by the final assembly plant.
What is the difference between Muncie M22 and M21?
The M22 to come later in 1967-’74 is also a close-ratio unit, but much stronger than the M21, with a higher torque capacity. Because the Muncie has so much in common with the T-10 and even similar Saginaw boxes, it is easy to get this guy mixed up with non-Muncie units.
Why is M22 called rock crusher?
M22 gears are also made of a higher-grade nickel alloy. The M20 and M21 cluster gears are cut at a 45-degree angle. The reduced gear angle of the M22 created a problem with noise (hence the name “rock-crusher”).
What is the difference between M20 and M21 gearbox?
Getting back to the HQ type M20 (6cyl & 253 V8 only) its 1st gear ratio is 3.07, the M21 (308 & 253 only) has a 1st gear ratio of 2.54. The M22 (6cyl One Tonners only) has a 1st gear ratio of 3.74. These boxes carry thru to the VK Commodre (M22 finished with the WB One Tonner).
What cars did the Muncie M22 come in?
From 1965-onwards the Rock Crusher was available with the Corvette, and by 1969 it was found on vehicles as diverse as the Chevelle, the Camaro, and the Oldsmobile 442. If a car made big power, chances are a Muncie M22 was on the menu.
What is a M21 transmission?
The Muncie M21 is a close-ratio unit originally designed to be matched with 4.11:1 or 4.56:1 GM 4 Series differentials. The M21 was for higher performance cars. A close-ratio gearbox keeps shift points closer together, which keeps rpms up.
How do I identify a GM 4 speed manual transmission?
Steps to Identifying a Four-Speed Manual Transmission
- Shape and Parts. Borg-Warner is the most clear-cut.
- Model Specifics. Each model within the make’s line typically has slight variations that can pinpoint a range or maybe even a specific year.
- Materials.
- Casting Number.
- Serial Number.
- Muncie Serial Number.
What cars came with a Muncie M22?
Does M22 have straight cut gears?
Muncie M22 4 Speed Transmission Close Ratio (Heavy Duty Straight Cut Gears)
Why is the Muncie M22 called the rock crusher?
What is the gear ratio of a Muncie M21?
2.20:1 ratio
The 2.20:1 ratio first gear is usually referred to as the Muncie M21 transmission; based on GM’s production codes.
What year did the Muncie M21 come out?
1963
He tells us both the M20 wide-ratio and M21 close-ratio transmissions were first offered in 1963. The M22 Rock Crusher would come later to accommodate the heavy twist of Chevrolet’s big-blocks in the mid-1960s….21.
| Muncie Four-Speed Gear Ratios | |
|---|---|
| M20 Wide-Ratio 1963-’65 | |
| M21 Close-Ratio | |
| First Gear | 2.20:1 |
| Second Gear | 1.64:1 |
What is on the transmission identification tag?
The ID of ALL B/W and Tremec transmissions is found on a metal tag bolted to the main case. The number found on the main case or tail shaft housing will not ID the transmission.
How strong is a Muncie M22?
A Muncie M22 is only rated to 500 lb ft (matched to the output of a 454 LS6).